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A.C. CHARACTERISTICS
TA
=
O°C
to
70°C,
VSS
=
OV,
(Note 1)
BUS PARAMETERS
READ
CYCLE:
Symbol
Parameter
tAR
Address
Stable
Before READ
tRA
Address Hold Time for READ
tRR
READ
Pulse Width
tRol21
Data Delay
from
READ
tAO[21
Address
to
Data Valid
tOF
READ
to
Data Floating
tRCY
Read Cycle
Ti
me
WRITE CYCLE:
Symbol
Parameter
tAW
Address Stable Before
WR
ITE
tWA
Address Hold Time for
WR
ITE
tww
WR
ITE Pulse Width
tow
Data
Set
Up Time for
WR
ITE
two
Data Hold Time for
WR
ITE
Notes:
1.
8279,
VCC
=
+5V
±5%;
8279·5,
VCC
=
+5V
±10%.
2.
8279,
CL
= 100pF; 8279-5,
CL
= 150pF.
OTHER
TIMINGS:
8279, 8279-5
8279
8279·5
Min. Max. Min. Max.
Unit
50
0
ns
5 0
ns
420
250
ns
300
150
ns
450
250
ns
10
100
10
100
ns
1 1
IlS
8279
8279·5
Min.
Max.
Min. Max.
Unit
50 0
ns
20 0
ns
400
250 ns
300
150
ns
40
0
ns
8279
8279·5
Symbol
Parameter
Min.
Max. Min. Max.
Unit
t¢w
Clock
Pu
Ise
Width
tCY
Clock Period
Keyboard Scan Time:
Keyboard Debounce Time:
Key
Scan Time:
Display
Scan Time:
5.1 msec
10.3
msec
80llsec
10.3
msec
230
500
120
320
Digit·on
Time:
Blanking
Time:
Internal Clock Cycle:
INPUT
WAVEFORMS FOR A.C. TESTS:
u=x
x=
2.0 2.0
? TEST POINTS <
O.B
O.B
tI.4ti
9-79
nsec
nsec
480llsec
160llsec
10
11
sec
AFN-00742A-10